The present invention pertains to the area of field emission devices and, more particularly, to methods for improving the uniformity of emission current of a field emission display.
Field emission devices having surface electron emitters are known in the art. It is further recognized in the art that surface electron emitters provide advantages over Spindt tip emitters because surface emitters can produce a greater current density than tip emitters. Surface emitters also allow for use of greater device dimensions, thereby relaxing error tolerances.
However, prior art surface emitters are commonly plagued with emission currents that are non-uniform over the emission surfaces. One prior art scheme for addressing the nonuniformity is taught by Pan et al in U.S. Pat. No. 5,857,882, entitled xe2x80x9cProcessing of Materials for Uniform Field Emission.xe2x80x9d Pan et al teach the use of an electron-emitting film, which is made from polycrystalline diamond, diamond-like carbon, graphite, or amorphous carbon. Pan et al further teach improving the emission uniformity of the film by conditioning the surface thereof. Pan et al teach that the conditioning is accomplished by scanning a metal electrode over the surface of the film. It is believed that this scheme increases the number of emission sites per unit area of the film. However, each individual emission site is capable of emitting a site current. Non-uniformity of the overall emission current can result from non-uniformity among the site currents. Pan et al do not teach a readily controllable method for improving uniformity among the site currents. Furthermore, the scheme taught by Pan et al is time consuming and may cause damage to a field emission device due to arcing.
Accordingly, there exists a need for a method for improving the uniformity of the emission current of a field emission device having surface emitters.